Disease activity, burden and suffering in patients with ulcerative colitis in the UK cohort recruited into the global ICONIC study

OBJECTIVE

The Understanding the Impact of Ulcerative Colitis and Its Associated Disease Burden on Patients (ICONIC) was a 2-year, global, prospective, observational study assessing disease burden in adults recently diagnosed (≤36 months) with ulcerative colitis (UC) receiving routine outpatient care, irrespective of disease severity or treatment. A subanalysis was conducted to understand the UK perspective.

DESIGN/METHOD

All eligible consenting patients enrolled in ICONIC from the UK were included in the subanalysis of patient-reported and physician-reported outcomes at baseline and year 2 (Y2).

RESULTS

Sixty-three UK patients were included (mean age 43.4 years, 58.7% female). At baseline and Y2, the mean (±SD) Simple Clinical Colitis Activity Index (SCCAI) scores were 3.6 (±3.3) and 1.5 (±1.5); Patient Modified Simple Clinical Colitis Activity Index (P-SSCAI) were 4.9 (±4.0) and 2.6 (±2.6), respectively. Physician-reported Pictorial Representation of Illness and Self Measure (PRISM) median scores (assessing inverse of suffering) were 3.5 (IQR 2.0-6.8) at baseline and 5.5 (IQR 3.6-6.9) at Y2; patient-reported PRISM scores were 4.7 (IQR 2.6-6.9) and 5.4 (IQR 3.2-8.0), respectively. At baseline, SCCAI and P-SCCAI were strongly correlated (r=0.86, p<0.0001), and patient-reported and physician-reported PRISM scores moderately correlated (r=0.67, p<0.0001). At Y2, moderate correlations were observed (SCCAI vs P-SCCAI: r=0.72, p<0.0001; patient-reported vs physician- reported PRISM: r=0.60, p<0.0001). Rating Form of IBD Patient Concerns scores indicated patients' greatest concerns were with energy level, having an ostomy bag and effects of medication (baseline scores >3.0).

CONCLUSIONS

These findings demonstrated the multifaceted burden of disease in patients recently diagnosed with UC in the UK. Agreement between patients and physicians on disease activity/severity varied according to the instrument used.

Hemopoietic cell expression of the chemokine decoy receptor D6 is dynamic and regulated by GATA1

D6 scavenges inflammatory chemokines and is essential for the regulation of inflammatory and immune responses. Mechanisms explaining the cellular basis for D6 function have been based on D6 expression by lymphatic endothelial cells. In this study, we demonstrate that functional D6 is also expressed by murine and human hemopoietic cells and that this expression can be regulated by pro- and anti-inflammatory agents. D6 expression was highest in B cells and dendritic cells (DCs). In myeloid cells, LPS down-regulated expression, while TGF-beta up-regulated expression. Activation of T cells with anti-CD3 and soluble CD28 up-regulated mRNA expression 20-fold, while maturation of human macrophage and megakaryocyte precursors also up-regulated D6 expression. Competition assays demonstrated that chemokine uptake was D6 dependent in human leukocytes, whereas mouse D6-null cells failed to uptake and clear inflammatory chemokines. Furthermore, we present evidence indicating that D6 expression is GATA1 dependent, thus explaining D6 expression in myeloid progenitor cells, mast cells, megakaryocytes, and DCs. We propose a model for D6 function in which leukocytes, within inflamed sites, activate D6 expression and thus trigger resolution of inflammatory responses. Our data on D6 expression by circulating DCs and B cells also suggest alternative roles for D6, perhaps in the coordination of innate and adaptive immune responses. These data therefore alter our models of in vivo D6 function and suggest possible discrete, and novel, roles for D6 on lymphatic endothelial cells and leukocytes.

Hemopoietic cell expression of the chemokine decoy receptor D6 is dynamic and regulated by GATA1

D6 scavenges inflammatory chemokines and is essential for the regulation of inflammatory and immune responses. Mechanisms explaining the cellular basis for D6 function have been based on D6 expression by lymphatic endothelial cells. In this study, we demonstrate that functional D6 is also expressed by murine and human hemopoietic cells and that this expression can be regulated by pro- and anti-inflammatory agents. D6 expression was highest in B cells and dendritic cells (DCs). In myeloid cells, LPS down-regulated expression, while TGF-beta up-regulated expression. Activation of T cells with anti-CD3 and soluble CD28 up-regulated mRNA expression 20-fold, while maturation of human macrophage and megakaryocyte precursors also up-regulated D6 expression. Competition assays demonstrated that chemokine uptake was D6 dependent in human leukocytes, whereas mouse D6-null cells failed to uptake and clear inflammatory chemokines. Furthermore, we present evidence indicating that D6 expression is GATA1 dependent, thus explaining D6 expression in myeloid progenitor cells, mast cells, megakaryocytes, and DCs. We propose a model for D6 function in which leukocytes, within inflamed sites, activate D6 expression and thus trigger resolution of inflammatory responses. Our data on D6 expression by circulating DCs and B cells also suggest alternative roles for D6, perhaps in the coordination of innate and adaptive immune responses. These data therefore alter our models of in vivo D6 function and suggest possible discrete, and novel, roles for D6 on lymphatic endothelial cells and leukocytes.

Unique features and distribution of the chicken CD83+ cell

The central importance of dendritic cells (DC) in both innate and acquired immunity is well recognized in the mammalian immune system. By contrast DC have yet to be characterized in avian species despite the fact that avian species such as the chicken have a well-developed immune system. CD83 has proven to be an excellent marker for DC in human and murine immune systems. In this study we identify chicken CD83 (chCD83) as the avian equivalent of the human and murine DC marker CD83. We demonstrate for the first time that unlike human and murine CD83, chCD83 is uniquely expressed in the B cell areas of secondary lymphoid organs and in organs with no human or murine equivalent such as the bursa and Harderian gland. Furthermore through multicolor immunofluorescence, we identify chCD83(+) populations that have unique attributes akin to both DC and follicular DC. These attributes include colocalization with B cell microenvironments, MHC class II expression, dendritic morphology, and distribution throughout peripheral and lymphoid tissues.

Professional and part-time chemokine decoys in the resolution of inflammation

Inflammation is essential for protection from infection and for the repair of damaged tissue. Much is now known about how inflammation is induced and maintained, but the processes underlying the resolution of inflammation are often overlooked. However, resolution is an essential component of all successful inflammatory responses because it ensures the restoration of tissue homeostasis and prevents immunopathology of the type seen in chronic inflammatory diseases and autoimmunity. Small secreted proteins called chemokines, acting through chemokine receptors, are known to be critical regulators of leukocyte recruitment and function during the initiation and maintenance of inflammation. Thus, their efficient removal would seem to be a prerequisite for successful resolution. In recent years, it has emerged that specialized chemokine "decoy" receptors exist that actively participate in this process. Moreover, other chemokine receptors have been proposed to lead a double life and perform opposing roles during inflammation: leukocyte recruitment (by signaling) and resolution (by chemokine sequestration). A recent study provides further support for this theory by showing that apoptotic inflammatory leukocytes increase the number of surface chemokine receptors and that these receptors can remove chemokines from inflamed tissue. Leukocyte apoptosis is already known to aid resolution, not just because it eliminates leukocytes from inflamed tissues, but also because their consumption by macrophages leads to the production of anti-inflammatory cytokines. The new work indicates that chemokine sequestration may be another mechanism exploited by dying cells to assist in the resolution of inflammation.